He learned from the last time he got exposed that quickly by Alpha.
Wonder if he learned enough with Delta or if she would still instantly recognize him.
I feel like this is a case where the translator should have just left it as -sama instead of translating it to Lady.
It's not like most people reading this won't know what -sama is, and even if they don't, it won't cause the confusion of why they thought she was a boy but called her Lady.